Sponges and sponge devices are currently in widespread use for the removal and management of liquids that are produced at or introduced to a surgical site. One form of such device, called a surgical spear, is typically used in the performance of micro-surgical procedures such as eye surgery, plastic surgery, hand surgery, and the like, and will generally consist of a small sponge element to which a plastic handle is molded. Ophthalmic sponge rings are used to help keep topical anesthesia in contact with the eye during surgery, and eye drains serve to automatically and continuously wick fluid away from a surgical site; pieces of sponge sheet are used as wipes for surgical instruments and the like.
It is of course of critical importance that a surgical sponge be both sterile and also at least substantially free from foreign matter that is loose or is subject to being dislodged. Even if the sponge material does not inherently contain fragments (as is true of sponges produced from synthetic resinous materials such as, for example, polyvinyl alcohol and polyvinyl acetal), it has been appreciated that particulates are produced when a sponge is cut to a desired shape; the problem is exacerbated when a point or other small dimension is produced on the sponge element. Such sponges and sponge devices are normally furnished in protective packaging which may, in certain instances, be made of a moisture-barrier material and sealed to prevent the passage of water vapor.
The surgical spear was originally developed in the late 1960""s as a device having a compressed regenerated cellulose sponge element that would rapidly remove fluids from around the eye during ophthalmic surgery. When the sponge element of the spear was brought into contact with liquid (primarily saline, used to keep the eye from drying under hot operating room lights) it would rapidly absorb and expand to its full holding capacity, whereupon it was discarded and replaced by another spear to provide a fresh, compressed sponge element.
Drawbacks inherent in the use of cellulose sponge elements include their lack of biocompatibility and a high lint and fiber content. Moreover, particulates produced during cutting become embedded in the surfaces of the compressed sponge, and are especially susceptible to being released upon expansion of the sponge during use, ultimately tending to infect the eye, particularly when encapsulated, and necessitating antibiotic treatment.
Surgical spears having polyvinyl alcohol (PVA) sponge elements were introduced in the mid- to late 1970""s. It was anticipated that PVA would replace cellulose as the sponge element of choice, because the material is biocompatible, contains no inherent lint or fiber, and produces substantially less debris when cut. However, PVA sponges failed to absorb and expand as quickly as cellulose and, being much less dense than cellulose, they lacked the stiffness that is desired to enable manipulation of tissue during surgical procedures. Factors such as these caused many surgeons to continue specifying the use of cellulose spears.
Although there have been few changes in the design and construction of surgical spears in the interim, the introduction of laser surgery has given new impetus to the demand for xe2x80x9cparticulate-freexe2x80x9d sponge material. One such procedure is laser in situ keratomileusis (LASIK) surgery, which is a modification of the original Barraquer keratomileusis procedure. The LASIK procedure is considered to be superior for correction of high myopia, and is thought to overcome many problems associated with PRK; a more rapid stabilization of refraction is achieved, and postoperative pain is reduced. Also, Bowman""s layer and the epithelium are preserved at the optical axis, which seems to result in the production of almost no haze.
There are as well, however, potential problems associated with LASIK procedures, starting with the use of the microkeratome and including performing the photoablation. Additional complications include incomplete disc resection thin flap, loss of flap, or bottomholing of the flap (albeit good surgical skills and better microkeratomes can minimize them). Laser decentration, displacement, wrinkling, and edema of the flap, and lipid or epithelial deposits within the interface may also occur.
In any of event, the introduction under the cornea of lint, fibers, or other fragments larger than a certain size can cause (in addition to pervasive foreign-body concerns) refraction of light, and can thereby seriously affect the vision of the patient; consequently, the presence of such matter cannot be tolerated. Even apart from its lack of biocompatibility, these constraints virtually preclude the use of cellulose spears during LASIK surgery. And while PVA sponge elements have a much reduced inherent debris content, and indeed manufacturers have heretofore regarded them to be fiber- and lint-free, it has now been appreciated that the requisite level of purity has not been afforded, especially in respect of the demands of surgeons performing LASIK procedures.
Richter et al. U.S. Pat. No. 3,566,871 is directed to a polyurethane sponge which, albeit designed for disposability, may be washed, resterilized, and reused. In accordance with the preferred method disclosed a recirculating line is provided to remove loose pieces of foam, following which the foam body passes under infrared lamps to remove water. The dry sponge is cut into the desired size, and the resultant sponge pieces are packaged and sterilized.
Vaughn U.S. Pat. No. 2,613,862 provides a method of packaging a sponge in a wet and expanded state. DeBusk U.S. Pat. No. 5,725,517 discloses a method for making a surgical sponge from a woven web, wherein cut edges of the sponge element are folded inwardly prior to washing. Georgevich U.S. Pat. No. 4,291,697 discloses a sponge having a handle, Smith U.S. Pat. No. 3,717,244 discloses a packaged surgical sponge, and Korteweg U.S. Pat. No. D421,302 discloses a surgical spear.
The broad objects of the present invention are to provide a novel method for the production of a surgical sponge product that is at least substantially free from particulates and other debris, and to provide a novel surgical sponge product having that characteristic.
More specific objects of the invention are to provide such a method and sponge product whereby and wherein the product is enclosed in a packaging component which may desirably be fabricated from a non-barrier material and/or left in an unsealed condition.
A further specific object of the invention is to provide a surgical product, and a surgical device incorporating it, and especially a surgical spear, wherein the sponge product is sufficiently free of debris as to render it uniquely suited for use in LASIK surgery and like microsurgical procedures. Such a product will contain few if any particles that are visible at 20 power (or lower) magnification, and may be characterized as essentially particulate free.
As used herein, the phrase xe2x80x9csponge elementxe2x80x9d will generally refer to a piece of sponge cut from a xe2x80x9csponge member.xe2x80x9d The phrase xe2x80x9csponge productxe2x80x9d will generally refer to a sponge element that has been processed, in accordance with the invention, to render it at least substantially particle-free, and a sponge element or product combined with another component (e.g., a handle) will generally be referred to as a xe2x80x9csponge device.xe2x80x9d
It has now been found that certain of the foregoing and related objects of the invention are readily attained by the provision of a method for the production of a packaged surgical sponge product, comprising the steps: providing a surgical grade sponge member; cutting the sponge member, in at least a primary cutting operation, to produce at least one sponge element defined by at least one exposed cut surface; thereafter washing the sponge element to produce a substantially particulate-free sponge element, comprising a sponge product, and packaging the sponge product in a packaging component to substantially enclose it. The method will preferably include a further step of attaching at least one handle to the sponge member prior to the primary cutting operation, ultimately to produce a sponge device comprised of the sponge product and the attached handle.
In certain embodiments the sponge product will be maintained in the expanded state subsequent to the washing step and until completion of the packaging step. The sponge product may be dried before the packaging step is carried out; it will desirably be fabricated from a material that exhibits dimensional stability in the compressed, dry state (even though it is packaged in the dry, expanded state), in which case the packaging component may advantageously be fabricated from a water vapor-permeable material and/or be left unsealed.
In other embodiments of the method a substantial amount of liquid may be maintained in the sponge product, through completion of the packaging step, with the packaging component being fabricated from a water vapor-barrier material and being sealed in the packaging step; such an amount of residual liquid will generally be that which is just sufficient to keep the sponge soft and supple. Alternatively, the sponge product may be dried and compressed subsequent to the washing step, and packaged in the same manner (but in that case, to prevent rehydration).
The cutting step of the method may include a secondary cutting operation intervening between the primary cutting operation and the washing step. In those instances in which the sponge member is fabricated from a material that exhibits dimensional stability in the compressed, dry state, the primary cutting operation will desirably be carried out with the sponge member in that state, with the secondary cutting operation being carried out with the sponge element in the expanded state. Such a method will include a further step, intervening between the primary and secondary cutting operations, of wetting the sponge element to effect its expansion; the element may or may not be recompressed subsequently.
In those embodiments in which the method includes a handle-attaching step, that step will normally be completed prior to the primary cutting operation. A multiplicity of handles may be formed simultaneously, with the primary cutting operation thereafter being performed to produce a multiplicity of sponge elements (and ultimately, sponge products) to each of which a handle is attached.
Other objects of the invention are attained by the provision of a surgical sponge product, and the corresponding packaged article, made in accordance with the method embodiments described. Sponge devices provided in accordance herewith will preferably comprise surgical spears and, in particular, spears that are especially adapted (by virtue of essential freedom from particulates) for use during ophthalmic (and particularly, LASIK) surgery.